One common interpretation of this passage of Mark is that Christians must keep themselves separate from evil and sin in order to remain near to God in themselves. If this requires denying or removing some aspect of themselves, then that is a price they must be willing to pay because it would be better to go to heaven without that part of themselves than to remain whole but also in the fires of hell.
Some Christians have taken all of this literally and have gone so far as to cut off pieces of their body in order eliminate any temptations those body parts. Even many Christian theologians have recognized, however, that taking these lines literally is to seriously misunderstand them because earlier statements of Jesus argue that that which is unclean comes not from the outside, but rather from a persons heart and mind.
If that is the case, then we must conclude that temptation, too, is more a product of hearts and minds than of hands and feet. Even if we attribute temptations to Satan, it would still be an error to blame our eyes. So how should we read this? I think that the point being made is that temptation can be very much a part of our lives but that, in order to avoid temptation, sometimes we may have to cut ourselves off from some aspect of our lives.
We might, for example, be living in a dysfunctional relationship where a person is a constant source of temptation, such as, always offering us drugs or alcohol. This may be a very old relationship which we find very comforting most of the time, but Jesus message is that it would be better for us to give it up rather than give in to the temptations it forces upon us.
The fate of those who give in to temptation is, however, rather disturbing. This isnt the only passage where Jesus emphasizes the idea that those who do not follow him are destined to spend eternity in torment down in hell. One has to wonder what sort of love Jesus is here to share when such a penalty awaits those who dont accept that love.
To say love me or I will punish you and make your existence one of suffering and torment is characteristic of an abusive boyfriend or husband and we dont normally say that such people really love their partners. They may think that they love, but in fact they have confused power and control for love and kindness. The same might be said here about Jesus and God: instead of accepting people unconditionally, despite their flaws and faults, Jesus is insisting that the only way he will accept them is if they can fit into his model of how humans should behave, specifically by following him and obeying his commands.
It should not be assumed that such an attitude is unique to Christianity. On the contrary, this was very much in keeping with Jewish traditions. Similarly dysfunctional ideas about how God relates to humanity can be found throughout the Old Testament in the descriptions of how God treats the nation of Israel. Marriage and even rape are used in places like the Book of Hosea, Ezekiel, and Jeremiah as metaphors for the relationship between God and the Jews. The appropriate response of God to Israels infidelity is chastisement and punishment; only when they agree to be subservient and obedient are they again shown anything like affection and tenderness.